Small intestinal transit time affects methotrexate absorption in children with acute lymphoblastic leukemia

Area of Science:

• Pharmacokinetics
• Pediatric Oncology
• Gastroenterology

Background:

• Methotrexate (MTX) is a key chemotherapy agent for acute lymphoblastic leukemia (ALL).
• Understanding factors influencing MTX oral absorption is crucial for optimizing treatment efficacy and minimizing toxicity in pediatric patients.
• Small intestinal transit time (SITT) is a potential determinant of oral drug absorption.

Purpose of the Study:

• To investigate the relationship between SITT and MTX absorption parameters in children with ALL.
• To identify an optimal SITT range for maximizing MTX bioavailability.

Main Methods:

• Serum MTX concentrations were measured in 28 children with ALL after oral administration.
• SITT was assessed using the lactulose breath test (mouth to caecum).
• Correlation analysis was performed between SITT and MTX absorption parameters (e.g., time to peak concentration, absorption profile).

Main Results:

• SITT varied significantly among children, ranging from 30 to 240 minutes.
• Longer SITT was associated with delayed peak MTX concentrations and a more erratic absorption pattern, sometimes with biphasic peaks.
• An optimal SITT range of 90-105 minutes was identified for MTX absorption.
• Both faster (<90 min) and slower (>105 min) SITT resulted in lower peak MTX concentrations relative to the administered dose.

Conclusions:

• SITT is a significant factor influencing oral MTX absorption in pediatric ALL.
• Maintaining an optimal SITT (90-105 min) may enhance MTX bioavailability and therapeutic effect.
• Further research could explore interventions to modulate SITT for improved MTX pharmacokinetics in children.